Background: The quadrivalent human papillomavirus vaccine (qHPV) is FDA-approved for use in males 9 to 26 years old to prevent anogenital condyloma. The objective of this study is to determine if qHPV is effective at preventing anal condyloma among men who have sex with men (MSM) aged 26 years and older. Methods: This post-hoc analysis of a nonconcurrent cohort study evaluated 210 patients without history of anal condyloma and 103 patients with previously-treated anal condyloma recurrence-free for at least 12 months prior to vaccination/time zero. We determined the rate of anal condyloma development in vaccinated versus unvaccinated patients. Results: 313 patients with mean age 42 years were followed for median 981 days. During 773.6 person-years follow-up, condyloma developed in 10 (8.6%) vaccinated patients (incidence of 3.7 per 100 person-years) and 37 (18.8%) unvaccinated patients (incidence 7.3 per 100 person-years; p = 0.05). Multivariable hazards ratio showed that qHPV was associated with decreased risk of anal condyloma development (HR 0.45; 95% CI 0.22-0.92; p = 0.03). History of anal condyloma was associated with increased risk of anal condyloma development (HR 2.28; 95% CI 1.28-4.05; p = 0.005), as was infection with oncogenic HPV (HR 3.87; 95% CI 1.66-9.03; p = 0.002). Conclusions: Among MSM 26 years of age and older with and without history of anal condyloma, qHPV reduces the risk of anal condyloma development. A randomized controlled trial is needed to confirm these findings in this age group.